Were you using WSL 1 or 2? WSL 1 networking didn't work the way I expected, but WSL 2 seems to support proper Linux networking since it's just a Linux VM under the hood.

Conceptually this makes sense. It doesn't really run Under windows, it runs beside windows. Unlike WSL1 which was basically part of Windows. It's strange tcpdump doesn't run though as WSL2 is running a real kernel.

Personally I really liked the resource efficient WSL1 approach and I lament that they dropped it. But I know for some usecases (e.g. docker) a real Linux kernel was needed.

>It's strange tcpdump doesn't run though as WSL2 is running a real kernel.

It works just fine. Just tested it

Try dumping UDP packets from the host to the WSL machine...

The WSL machine is a Hyper-V VM. Why would you expect the default configuration to be able to sniff traffic from the host operating system? That would be a massive security hole.

I’m taking about traffic sent to the guest not on the interfaces.

It was theoretically more resource efficient but practically worse and harder to optimize. A state of affairs that VMware has exploited for a couple decades.

Better yet just install linux and if you need windows, use it in a locked down VM